Background: Few nutrition interventions in kindergarten classes have been evaluated, and none has been tested for program effectiveness, implementation, and dissemination. Building a Healthy Me (BHM) is a nutrition intervention for kindergarteners that is classroom-based and includes a family component. This study evaluated the public health impact of BHM in California kindergarten classrooms using the RE-AIM (reach, efficacy, adoption, implementation, and maintenance) framework. Methods: A quasi-experimental design assessed pre-to-post changes in nutrition knowledge, dietary consumption, and parent behaviors of 25 intervention classrooms (414 students, 264 parents); and postintervention differences in nutrition knowledge between the intervention classrooms and 4 control classrooms measured at postintervention only (103 students). Results: Intervention students improved in knowledge of food groups and healthy breakfast/snack options, and scored higher than control students in food group knowledge at postintervention (ps < 0.05). Parents of intervention group children increased their use of food labels, and intervention group children increased intake of several healthy foods and decreased intake of candy and fried potatoes (ps < 0.05). The BHM program reached 41% of kindergarteners attending public schools in California, and teachers implemented most lesson material. Conclusions: The BHM program was effective, implemented with fidelity, and broadly disseminated, highlighting its potential public health impact for kindergarteners.